Shell-dam.



PATENTEP FEB. 11, 1908.

B. B. JENNINGS.

SHELL DAM. APPLICATION FILED OUT. 21, 1907.

. I. l c 1 V N i f m7 w I 8 Wm m EDWIN B. JENNINGS, OF NEW YORK, N. Y.

SHELL-DAM.

Specification of Letters Patent. 7

Application filed October 21.1907- Sarial No 398.356.

. Patented Feb. 1 1,:1eoa= maximum degree of strength, rigidity andstability. I

According to my present invention my improved (lam isarched and ofsubstantially semi-elliptical form in cross sectionat the lower part,which imparts to the said lower art an extended base or broad support:-

This lower part is provided with an upper part forming a risingextension thereof and the surface of the lower part and this upperortion on the side of the impounded water is substantially an ogeecurve, the u per limb of which comes over and above t e u per part ofthe arch, thus throwing the weig t of I the impounded water for nearlyhalf its depth upon t e up er and stronger part of the arch tending tormly seat the same to its bed while the thrust of the im ounded watertending to un-seat the dam as this weight as an off-set this thrust uponthe up er limb.

of the ogee curve pullingfrom the ower or foundation end of this ogeecurve. Theidown stream wall or apron of the dam- 1 is inclined andcurved slightly but is suflia I ciently' straight to constitute a struthaving a direct thrust strain applied thereto*b'y the impounded] wate'rto the foundations thereof. 1 I e The details ofthe foundation for myimproved shell dam and the internal construction thereof form no part ofmy present invention.

In the drawing, Figuresl and 2 are vertical sections representing formsof my invention.

a represents the rock or. earth bed (prepared to receivesuitable'foundations b, an 0 repre sents" the semi-.elli tical wall ofmy im proved shell or hol ow dain-ofnoncrete, of any desired dimensions.The ends of the semi-elli tical wall therefore rest upon the indepen entfootings or foundations b.

Referring particularly to Fig. 1, I build{ upon this semi-ellipticalwall an upper portion, extension or prolongation d havingan; opening dtherein for the ur ose of reduc: ing the wei ht and material? he outersur face 2 of this wall and the upper portion don the u -strean1 sideagainst which the impounded water bears 1s an ogee curve, the convexmember of which is the outer surface of the wall 0 and the concavemember of, which is the outer surface of the extensionorf. upper portiond. This concave ortion or, upper limb is continued out from t e convex.portion near the up er part of the wall 0,

starting at slightly a ove half the depth of the impounded water;therefore the said shell dam on'th inner surface receives an.appreciable amount of the weight of the im 'pounded water, tendin tofirmly seat the same to its bed,,while t e thrust of the im.

"pounded water tending to 'lift' the dam off the tend to liftthis-weight seat must of necessity h d t e curve member of of water andto pul time the outer: slightly, curved but almost, straight surface ofthe dam forms a strut in the dam from its foundation at the same theintegral structure, tending with this movement to force the outerportion of the dam more firmly to its foundation; Thus thevariousstrainstend to compensate one another so that the dam maintains its poshtion carrying the weight and pressure of water behind them or on theup-stream side.

,The'i'opening d in then per member d is simply to reduce the weig' t ofthe shell or hollow dam and the amount of materials employed.

The form of m invention shown'in Fig.1 v is. not only suita le for thefull length of a dam but; may also be employed as a structurefor thespill-way part of the dam; as the outer surface is eminently fitted forthe delivery of surplus water.

MReferring to Fig. 2, the description herein- I before made withreference to Fig. '1, answers essentially for'the form of my inventionshown in Fig. 2, except that in Fig. 2 the u er extension e from thesemi-elliptical we 0 1s thrown forward toward the down-stream side ofthe dam thus'bri nging even more of the weight of the im ounded water uon the darn strficturmyten ing to hold'it own in position the; ogeecurved surface 3 of this orm' of my invention being more renounced eventhan that in-Fi g -'1,"but't e" outer or 'down-streamwall orapron whilesuitable for the main portionof the darn would not be uite as suitableforthe spill-way portion, as t 1e same is slightly too vertical.

I claim as my invention: v

1. A hollow or shell dam of concrete comprising a semi-elliptical Wall,resting by independent footing upon a suitable foundation and a risingportion or extension from the upper part thereof.

2. A hollow or shell dam of concrete comprising a semi-elliptical wall,suitable foundations therefor, a rising portion or extension from the upor part thereof, said extension being of ho low construction and theupstream surface of the hollow dam being an ogee curve.

3. A hollow or shell dam of concrete comprising a semi-elliptical Wall,suitable founda tions therefor, a rising portion or extension from theup erpart thereof, said extension being of ho low. construction andthe-upstream surface of the hollow dam be an ogee curve and thedown-stream -wa or apron forming a strut having a direct thrust strainapplied thereto by the impounded 'water.

4. A hollow or shell dam of concrete comprising a semi-elliptical wall,suitable foundations therefor, a rising portion or extension from the.upper part thereof and which ex-- tension is formed integrally with thesemielliptical wall and mainly to one side of the vertical center ofsaid 'wall on the downstream side so that the weight of an appreciabledepth of the im ounded water rests upon the semi-elliptica wall.

Signed by me this 14th day of October I

